Assignment 2: Identifying Bacteria

In everyday life we run into millions of microbes. Some of the bacteria is capable of making humans sick. The study of microbes has become very important subject to help stop potential pandemics and ensure proper hygiene. Anthony van Leeuwenhoek was the first scientist who discovered bacteria. In my study of microbiology, I got to choose an unknown bacteria to identify. It is important to start off finding the family of the unknown bacteria and then eliminating one by one the species to know which bacteria it is. By knowing the family, a scientist can save themselves a lot of time by knowing which tests need to be performed for the elimination process. This might seem like a waste of time to one but being able to correctly identify bacteria

There are many types of bacteria that can be found in your bathroom. They might also be found on your toothbrush! I have been researching about what bacteria are lurking in my bathroom. I placed 6 petri dishes filled with agar in my bathroom. I left them there for 24 hours to collect bacteria samples.

The purpose of this lab was to identify two unknown bacteria from a mixed culture. The reason for identification of unknown bacteria was to help students recognize different bacteria through different biochemical tests and characteristics. This is important in the medical field because identification of unknown bacteria can help treat a patient by knowing the contributing source of a disease. Also knowledge of different bacteria helped others make antibiotics used today. This lab was completed by using the methods learned thus far in identification of bacteria.

For many years the identification of microorganisms has been important in the world of medicine. It is essential or correct disease diagnosis in patients and for proper treatment. Knowing the correct identity and characteristics of microorganism is crucial when disease outbreaks occur in populations, also knowing how humans can benefit from microorganisms is important; many can be used in making certain foods or antibiotics.

The first result of importance was the result of the Gram stain. The observations of the unknown bacteria from the slant culture after Gram staining showed that the unknown bacteria were Gram negative bacilli (Image 1). After determining the unknown bacteria was Gram negative, an oxidase test was conducted on a sample from the slant culture. The cotton swap with the sample of bacteria did not change color when the oxidase reagent was applied, thus providing a negative result. With a negative oxidase test, further tests were conducted to determine various characteristics of the unknown bacteria. A MR-VP broth was inoculated with a sample from a slant culture of unknown bacteria. After incubation, the methyl red reagent was added to the broth, and the broth turned red, providing a positive result (Image 2). An EMB agar streak plate was inoculated with a sample from a slant culture of the unknown bacteria, and after incubation, growth was found on the plate, providing a positive result (Image 3). A Citrate agar slant was inoculated, and after incubation, growth was found on the media, providing a positive result (Image 4). A Urea agar slant was inoculated, and after incubation, the agar had changed from a peach color to a bright pink color, providing a positive result (Image 5). Using the flowchart (Figure 1) developed from the Table of Expected Results, the lab partners started at the oxidase test. Given the negative result of the oxidase test, the flowchart is

Often scientists work with bacteria that do not come in a labeled test tube— for example, bacterial samples taken from infected human tissue or from the soil—and the scientist must then identify the unknown microorganism in order to understand what behavior to expect from the organism, for example, a certain type of infection or antibiotic resistance. However, because of the relatively few forms of bacteria compared to animals and because of the lack of bacterial fossil records due to their asexually reproductive nature, the taxonomy used to classify animals cannot be applied to bacteria (Brown 275). In order to classify unknown bacteria, a variety of physiological and metabolic tests are available to narrow a sample down from the fathomless number of possibilities into a more manageable range. Once these tests have been performed, the researcher can consult Bergey’s Manual of Determinative Bacteriology, a systematically arranged and continually updated collection of all known bacteria based on their structure, metabolism, and other attributes.

My unknown organism #6 is Morganella morganii, which is a gram-negative bacillus rods commonly found in the environment and also in the intestinal tracts of humans, mammals, and reptiles as a normal flora. (3, 5) This bacterium Morganella morganii, was first discovered in the 1906 by a British bacteriologist named H. de R. Morgan. (2) Despite its wide distribution, it is an uncommon cause of community-acquired infection and is most often encountered inpostoperative and other nosocomial settings. (2, 3) Morganella morganii infections respond well to appropriate antibiotic therapy; however, its

There are many reasons for knowing the identity of microorganisms. The reasons range from knowing the causative agent of a disease in a patient, so as to know how it can be treated, to knowing the correct microorganism to be used for making certain foods or antibiotics. This study was done by applying all of the methods that I have been learned so far in the microbiology laboratory class for the identification of an unknown bacterium.

Citrobacter Freundii is a species of bacteria that can be potentially harmful to humans. It is known to cause meningitis by protruding into the brain and replicating itself (1). The Citrobacter species has also been found as a cause of some urinary tract infections, diarrhea, and even gastrointestinal diseases and symptoms (3). C. Freundii can be located in a wide variety of soils and water (3). Lastly, it is also the cause of many nosocomial infections due to its presence in water (1).

The purpose of this study was to identify the unknown bacterium using biochemical tests and various methods that had been learned from previous the microbiology laboratory class. Identifying the unknown bacterium was determined by separating and differentiating possible

Morganella morganii is a gram-negative bacillus with no special arrangement. It is the third member of the tribe Proteeae. This bacterium was first discovered in the year 1906 by a British bacteriologist by the name of He. De R. Morgan. In the late year of 1939, the bacterium was named Proteus morganii, and again changed some years later due to findings that this bacterium did not obtain the ability to ferment all carbohydrates like the genus Proteus was capable of doing. Instead, researchers found the bacterium to have the capabilities of ferment only glucose and therefore its name had been changed one final time to Morganella (its own genus) morganii. While testing M. morganii, findings show that it has its own special characteristics that differ from the usual Proteea. M. morganii does not swarm on a nutrient agar plate like the typical Proteus would. It also does not produce the black precipitate found in Hydrogen Sulfide gas tests. M. morganii produces phenylalanine deaminase, which is the enzyme that wipes out the amino group, resulting in a phenyl pyruvic acid. It is a facultative anaerobe meaning that it is capable of producing energy in the form of ATP by aerobic respiration if oxygen is present in its environment. If oxygen is not present in the environment, the bacteria is fully capable of producing energy in anaerobic environments as well. Morganella morganii can be found in the soil, water, and feces. The bacteria is a common resident to the

The purpose of this study was to identify the unknown bacterium #305. This sample was collected from the urine of a 64 year old hospital patient named “Doris”. Several tests were conducted to determine the morphological and physiological characteristics of the unknown. These tests included but were not limited to: motility, gram staining, salinity tolerance, and fermentation of different substances. After assessing the observed results, the identity of unknown bacterium #305 was suggested to be Citrobacter freundii. The test results, with the exception of the urea test, were very consistent with the expected results.

There are three main types of media cultures: enriched, differential and selective. Each of these three cultures have different properties and aid in laboratory settings by distinguishing between different bacterial cultures. Enriched media allow the growth of multiple bacterial organisms due to the fact that they contain vitamins and nutrients, and do not contain compounds to deliberately inhibit the growth of microorganisms (Wessner et al. 2013). On the other hand, differential and selective media are used to differentiate between to similar types of bacteria, and to select for specific bacterial growth while inhibiting others, respectively (Wessner et al. 2013). Two main ways to distinguish bacteria are whether they are Gram

Life on this planet began with microorganisms. Through millions of years microorganisms have found ways to successfully adapt and survive. These adaptations have created a wide biodiversity, allowing them to basically populate in all places. Why are these microbes so important? Because they shape the history of our world. Some microbes can be deathly to humans while some others are favorable, for example, bacteria that lives in the gut of both humans and animals and helps during the process of digestion (Alfred Brown & Heidi Smith, 2006). Understanding these interactions help scientists to find ways to protect humans from potential deathly pathogens. In order to observe microbes, microscope proficiency and microorganisms’ identification are crucial skills in a microbiology lab. During this laboratory session, samples of environmental and human organisms were inoculated into two different rich media and incubated to their according temperature. After this, appropriate use and calibration of the microscope was performed. Lastly, morphology and size of different species of bacteria, algae, fungi and protozoan were recorded.

From the air we breathe to the water we drink to the food we eat, there are thousands upon thousands of bacteria that we interact with on a daily basis some are good and help us live healthy and productive lives, like the bacteria that is used to make and keep yogurt from spoiling (Wassenaar, 2002) . Now granted, not all bacteria are beneficial to us and can cause us a lot of harm. If bacteria are harming us, either by causing disease, contaminating our food, or harming the environment that we live in, one needs to identify the unknown bacteria so that the proper treatment and strategy can be developed to remedy the problem (Intrieri, 2014). In order to identify bacteria and other organisms, scientists have developed many different tests to differentiate microorganisms from each other their physical characteristics.